The present disclosure generally relates to methods, systems and apparatus for relieving fluid pressure from an organ such as (but not limited to) the eye. More particularly, the present disclosure relates to methods and apparatus for treating glaucoma by relieving the pressure within the eye.
Glaucoma is a disease of the eye that affects millions of people. Glaucoma is associated with an increase in intraocular pressure resulting either from a failure of the eye's drainage system to adequately remove aqueous humor from the anterior chamber of the eye or the overproduction of aqueous humor by the ciliary body. The build-up of aqueous humor and resulting intraocular pressure can cause irreversible damage to the optic nerve and the retina, which may potentially lead to irreversible retinal damage and blindness.
Presently, glaucoma can be treated in a number of different ways, The most widely practiced treatment of glaucoma involves delivery of drugs such as beta-blockers or prostaglandins to the eye (typically in the form of eye drops) to either reduce the production of aqueous humor or increase the flow of aqueous humor from the anterior chamber of the eye. Glaucoma may also be treated by surgical intervention such as trabeculectomy. Trabeculectomy or similar surgical procedures involve creating conduits between the anterior chamber and the various structures involved in aqueous humor drainage such as Schlemm's canal, the sclera, and the subconjunctival space in order to provide a pathway for the aqueous humor to exit the anterior chamber.
While these methods of treating glaucoma have been generally effective, they are not without their drawbacks. In the case of medicinal treatments of the eye, patient compliance is an issue because such treatments require regular (i.e., daily) intervention. With respect to surgical procedures such as a trabeculectomy, such procedures are very invasive and can cause irreversible changes to the eye. For example, trabeculectomy results in the permanent removal of a segment of the trabecular meshwork, inflammation and scarring in the quadrant of the eye where the surgery was performed, and the formation of a filtering bleb. Implantation of shunts such as the Molteno, Barveldt, or Ahmed shunts induce chronic foreign body reactions and the formation of a chronic subconjunctival bleb. In addition, such surgical treatment of glaucoma often requires long healing times and can result in certain complications such as infection, scarring, hypotony or cataracts.
More recently, less invasive surgical treatments have been developed. These treatments do not require incision into the conjunctiva of the eye. One example of a less invasive surgical procedure is described in U.S. Pat. No. 6,544,249, the entire disclosure of which is hereby incorporated by reference. U.S. Pat. No. 6,544,249 discloses methods and apparatus for introducing a small bioabsorbable and biocompatible drainage canal, referred to therein as a microfistula tube into the portion of the eye that extends from the anterior chamber to the sub-conjunctival space. The procedure described in U.S. Pat. No. 6,544,249 does not require incision of the conjunctiva. Instead, introduction of the bioabsorbable microfistula tube is accomplished by an ab interno approach—through the cornea of the eye to the desired location (between the anterior chamber and the sub-conjunctival space.) U.S. Pat. No. 6,544,249 also generally describes a delivery apparatus for introducing and implanting the bioabsorbable microfistula tube.
U.S. Pat. No. 6,007,511, the entire disclosure of which is incorporated herein by reference, likewise discloses less invasive methods and apparatus for treating glaucoma. As in the above-referenced U.S. Pat. No. 6,544,249, a bioabsorbable drainage tube is introduced into the area between the anterior chamber and the sub-conjunctival space to allow drainage of the aqueous humor from the anterior chamber of the eye. As in U.S. Pat. No. 6,544,249, incision of the conjunctiva is not required.
These new procedures for treating glaucoma offer the promise of a long term cure of glaucoma without the shortcomings of medicinal treatments and without the risks associated with the known and presently practiced surgical procedures described above. Accordingly, it would be desirable to provide improved methods, systems, channels and delivery apparatus for treating glaucoma specifically and for treating other conditions where drainage of accumulated liquid is desired or required.